Your Always-At-Hand Bottle Might Also Carry Bacteria And Other Toxins
While the water found at the tap is often as good as that found in bottled water, refilling and reusing bottled water bottles over and over may create an opportunity for unwanted bacteria and toxins.
For example, a recent study of water collected from water bottles at a Calgary elementary school found bacteria in the kids' bottles that would prompt health officials to issue boil-water advisories, had the samples come from a tap. The study, reported in the Canadian Journal of Public Health, collected samples of water from the water bottles of 76 elementary students. They found bacterial contamination in about a third of the samples collected, including some fecal coliforms.
"If a town water supply had fecal coliforms in it, it would have to be shut down," said Cathy Ryan, the University of Calgary professor who authored the study. "The bacteria likely came from the kids' hands and mouth over time as they repeatedly used the same bottles without washing them or allowing them to dry," Ryan said.
So, is the answer to wash out the water bottle in warm soapy water, rinse and let air dry each night? Yes, if it's a bottle designed for multiple uses. Even rinsing out and letting air dry overnight will help kill off bacteria. Many plastic-ware brands now market water bottle designs, some with handy foldable straws, attached insulation, belt clips and the like.
On the other hand, repeated washing and re-using of "single-use" bottles may be a different matter. Preliminary work at the University of Idaho has found that single-use soft-drink and water bottles begin to leach out unwanted chemicals when repeatedly re-used and re-washed. Such bottles are commonly made of polyethylene terephthalate, or PET, which may be considered safe for its intended use but which begins to break down when used over and over. One of the toxins the University of Idaho researchers repeatedly found in water samples from the reused bottles was DEHA, a carcinogen regulated in drinking water because it has been found to cause weight loss, liver problems or possible reproductive difficulties.
The bottom line? If you invest in a good quality water bottle, take care of it and your health by washing it out on a regular basis and letting it air dry. If you'd rather re-use the bottles that soft drinks and bottled water come in, then its best to re-use them only a couple of times before retiring them to the recycle bin.